package collection;

import java.util.*;

public class CollectionDome01 {
    public static void main(String[] args) {
        //Collection c = new ArrayList();
        Collection c = new HashSet();
        boolean success = c.add("one");
        System.out.println(success);
        c.add("two");
        c.add("three");
        c.add("four");
        int size = c.size();
        System.out.println(size);
        boolean isEmpty = c.isEmpty();
        c.clear();
    }
}
